1. Field of the Invention
The present invention relates to a motor controller for performing control of a motor using analog feedback signals from encoders for detecting position and/or velocity of the motor or a movable member driven by the motor.
2. Description of the Related Art
Encoders to respectively output analog feedback signals of sine waves of A phase and B phase are generally adopted as detectors for detecting position and velocity of a motor or a movable member driven by the motor. An offset as displacement from a set value of a central voltage of amplitude, the amplitude and phase difference of the analog feedback signals of sine wave vary. Therefore, the analog feedback signals are observed using a special measurement device such as an oscilloscope to obtain information on the offsets, the amplitudes and the phase difference, and the feedback signals are adjusted based on the observation.
In the conventional art, an expert in operation of the oscilloscope is required to obtain the information on the offsets, amplitudes and phase difference using the special device such as oscilloscope in adjusting and confirming the analog feedback signals, and it is further required to make judgment on necessity of adjustment of the signals based on the information displayed on the oscilloscope. Thus, it has been difficult to adjust and confirm the signals based on the information on the offsets, amplitudes and phase difference.
The present invention enables obtaining information on offsets, amplitudes and a phase difference of analog feedback signals from encoders with ease.
The motor controller of the present invention performs control of position or velocity of a movable member mechanically connected with a motor using analog feedback signals from encoders for detecting rotational position or velocity of the motor, or position or velocity of the movable member, and the motor controller includes means for displaying information on at least one of amplitudes, offsets and a phase difference of the analog feedback signals on a display section of the motor controller or a host controller connected with the motor controller. Thereby, status of the feedback signals from the encoders can be perceived.
Further, the motor controller of the present invention may include means for displaying results of comparison of amplitudes and/or offsets of the analog feedback signals with respective predetermined values on the display section of the motor controller or the host controller.
The display section of the motor controller may include a LED display device or a seven-segmented display device. The information on at least one of the amplitudes, the offsets and the phase difference may be obtained based on A/D conversion values of the analog feedback signals. The motor controller may include means for calculating at least one of the offsets, the amplitudes and the phase difference of the analog feedback signals of two different phases.